[Python-ideas] Revised**12 PEP on Yield-From

[Greg Ewing]

Jacob Holm wrote:

> In other words, the ValueError in the following example is swallowed by 
> close():
> 
>  >>> def foo():
> ...     yield 'bar'
> ...     raise ValueError('baz')
>  >>> g = foo()
>  >>> g.next()
> 'bar'
>  >>> g.close()

No, g never raises a ValueError here, because the raise
statement is not reached.

You need to wrap the yield in a try-except to catch the
GeneratorExit.

-- 
Greg